From f9792eb960ff729953115be2d66eeacd6f50bcca Mon Sep 17 00:00:00 2001
From: Peter Ferrie <peter.ferrie@gmail.com>
Date: Thu, 8 Aug 2019 18:08:23 -0700
Subject: [PATCH] support Sierra track-swap protection

---
 src/patchers/sierra13.a | 22 ++++++++++++++++++++++
 src/strings/en.a        |  2 +-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/patchers/sierra13.a b/src/patchers/sierra13.a
index 0558a65..86da6bc 100644
--- a/src/patchers/sierra13.a
+++ b/src/patchers/sierra13.a
@@ -7,6 +7,7 @@
 ; Cranston Manor
 ; Jawbreaker
 ; Missile Defense
+; Mission Asteroid
 ; Pegasus ][
 ; Threshold
 ;
@@ -33,6 +34,8 @@
          ldy   #$01
          jsr   modify
          !byte $AD ;LDA
+         lda   #$24
+         sta   $B91E
 .jmpexit
          jmp   .exit
 
@@ -79,6 +82,10 @@
          !byte $8D,$8C,$BE ;STA $BE8C
          !byte $A9,$B9     ;LDA #$B9
          !byte $8D,$8D,$BE ;STA $BE8D
+         lda   #<.swaptrk
+         sta   $BE7D
+         lda   #>.swaptrk
+         sta   $BE7E
 ++       pla
          clc
          adc   #$48
@@ -89,6 +96,21 @@
          !byte $A0,$B9
          bvc   .jmpexit
 
+.swaptrk
+         ldy   $478
+         cpy   #$c0
+         beq   .swapped
+         cmp   #2
+         bne   .try4
+         asl
+         bne   .swapped
+.try4
+         cmp   #4
+         bne   .swapped
+         lsr
+.swapped
+         jmp   $BA1E
+
          ;Threshold secondary protection
 
 +        ldy   #11
diff --git a/src/strings/en.a b/src/strings/en.a
index 5f9d543..92635fb 100755
--- a/src/strings/en.a
+++ b/src/strings/en.a
@@ -280,7 +280,7 @@ StringTableHigh
 ; can be set directly before calling PrintByID.
 ;
 .header
-         !text "Passport by 4am               2019-07-25",$00
+         !text "Passport by 4am               2019-08-08",$00
 .mainmenu
          !text "________________________________________",$8D,$8D,$8D,$8D,$8D,$8D,$8D,$8D
          !text "               "